Two-week inhalational toxicology studies in rodents indicated NOAELs for lung effects in rats and mice of 2 ppm and 4 ppm, respectively, although nasal cavity lesions were observed in both species at 1 ppm. A single 6-hour exposure in rats of 8 ppm caused 100% mortality from airway necrosis, indicating a steep dose-response relationship.

Toxicity to respiratory and other cells may be due to a high non-enzymatic reactivity with reduced glutathione (GSH) or SH groups in proteins, although a less rapid reaction with deoxyguanosine and its 5'-monophosphate in vitro also has been reported.